ConvertBox Logo
ConvertBox

Audio Converter

Convert audio between MP3, WAV, FLAC, AAC, M4A and OGG. Choose bitrate, mono/stereo and sample rate, up to 100MB per file — all in your browser.

How to Use

  1. Select an audio file to convert (MP3, WAV, FLAC, AAC, M4A, or Ogg — up to 100MB)
  2. Choose the output format — MP3 for universal playback, WAV for lossless, AAC (.m4a) for Apple devices, FLAC for archiving
  3. Pick a bitrate to match your goal: 128 kbps for voice, 192 kbps for standard music, 256 kbps for high quality
  4. Click the "Convert" button — processing runs locally via FFmpeg.wasm, so files never leave your device
  5. The converted file downloads automatically once finished
  6. Use the output in music libraries, podcast editors, car USB drives, or any media player

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

Supported formats include MP3, WAV, FLAC, AAC, and OGG.
Converting to lossless formats (WAV, FLAC) preserves quality. Converting to compressed formats (MP3, AAC) may slightly reduce quality depending on bitrate.
Currently, files are converted one at a time for best results.
If conversion fails: (1) use a file under 100MB, (2) try converting to MP3 first if using an uncommon format, (3) check that the file plays correctly in a media player, (4) refresh the page and retry.
No. FFmpeg.wasm runs the conversion in your browser — files never leave your device.
ID3 tags are preserved when converting between tag-aware formats (MP3, M4A, FLAC). Cover art is kept by default.
Different codecs use different compression. MP3 and AAC are lossy; FLAC and WAV are lossless. Size shifts are expected.
No. All operations are processed entirely inside your browser's local sandbox using client-side APIs (like WebAssembly, pdf-lib, or HTML5 Canvas). Your files and data never leave your device.
The tool is completely free with no usage limits. However, since processing occurs in your browser's memory, we recommend keeping file sizes under 50MB (especially for heavy files like PDFs or videos) to ensure stability.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.
Yes. Once the page and its local library dependencies are loaded in your browser, the conversion logic runs completely offline without needing an active internet connection.

Related tools

Cut Audio

Trim audio files to extract a specific clip. Set start and end time to the millisecond, supports MP3/WAV/FLAC/AAC up to 100MB — processed locally.

MP3WAVAAC
Get Started

Join Audio

Merge multiple audio files into one track. Reorder clips, add silence between them, supports MP3/WAV/FLAC/AAC — all processed locally in your browser.

MP3WAV
Get Started

Compress Audio

Compress MP3, WAV, FLAC, and AAC audio in your browser. Adjust bitrate to shrink size while preserving sound — files up to 100MB, no uploads required.

MP3WAVAAC
Get Started

Adjust Volume

Adjust audio volume from -20dB to +20dB without re-encoding loss. Supports MP3/WAV/FLAC/AAC up to 100MB, processed locally in your browser.

Get Started

Video → Audio

Extract audio from MP4, MOV, WebM and AVI videos. Save as MP3, WAV, AAC or FLAC, pick bitrate and trim — processed locally with FFmpeg.wasm.

Get Started
NEW

Audio to Text

Use your browser's speech recognition to convert audio or video into SRT, VTT, or plain text. Real-time, private, free.

Speech → Text
Get Started